Companies Act, 2013
138. Internal audit.
1. Such class or classes of companies as may be prescribed shall be required to appoint an internal auditor, who shall either be a chartered accountant or a cost accountant, or such other professional as may be decided by the Board to conduct internal audit of the functions and activities of the company.
2. The Central Government may, by rules, prescribe the manner and the intervals in which the internal audit shall be conducted and reported to the Board.